Aortic shunt for selective cerebral perfusion in stroke and cardiac arrest

ABSTRACT

An aortic shunt comprising a second tubular member nested within a lumen of a first tubular member, wherein aortic blood flows through the lumen of the first tubular member and oxygenated and/or cooled blood is infused through a lumen and distal port(s) of the second tubular member to perfuse the cerebral vasculature. Alternatively, a cooling cylinder is nested within the first member, such that aortic blood is cooled through the cylinder before being delivered to the brain. A venous return catheter comprising an elongate tubular member is also provided to remove and isolate the cooled blood entering through jugular veins from the blood entering through the subclavian veins, when the cannula is positioned in the superior vena cava. Methods of using the aortic shunt and/or venous return cannula in providing selective cerebral perfusion in patients suffering from stroke and cardiac arrest are also disclosed.

[0001] This is a divisional of U.S. application Ser. No. 09/658,482filed Sep. 7, 2000, incorporated herein by reference in its entirety.

FIELD OF THE INVENTION

[0002] The present invention relates generally to medical devices. Moreparticularly, the invention relates to methods and devices forselectively diverting blood flow to the cerebral vasculature from theaorta in patients having stroke or cardiac arrest. More particularly,the invention relates to apparatus and methods which provide an aorticshunt and a venous return cannula for augmenting and/or coolingoxygenated blood to the brain. The devices and methods also providemechanisms for variable blood flow through the aorta.

BACKGROUND OF THE INVENTION

[0003] Patients experiencing cerebral ischemia often suffer fromdisabilities ranging from transient neurological deficit to irreversibledamage (stroke) or death. Cerebral ischemia, i.e., reduction orcessation of blood flow to the central nervous system, can becharacterized as either global or focal. Global cerebral ischemia refersto reduction of blood flow within the cerebral vasculature resultingfrom systemic circulatory failure caused by, e.g., shock, cardiacfailure, or cardiac arrest. Within minutes of circulatory failure,tissues become ischemic, particularly in the heart and brain.

[0004] Cardiac arrest is defined as abrupt cessation of cardiac pumpfunction, e.g., from myocardial infarction with loss of substantialmuscle mass, acute myocarditis, or from depression of myocardialcontractility following prolonged cardiopulmonary bypass. Mechanicalabnormalities, such as severe valvular stenosis, massive aortic ormitral regurgitation, acutely acquired ventricular septal defects, canalso cause cardiac arrest by reducing cardiac output. Additional causesof cardiac arrest include arrhythmia, such as ventricular fibrillationand ventricular tachycardia.

[0005] With sudden cessation of blood flow to the brain, complete lossof consciousness is a sine qua non in cardiac arrest. Cardiac arrestoften progresses to death within minutes if active interventions, e.g.,cardiopulmonary resuscitation (CPR), defibrillation, use of inotropicagents and vasoconstrictors such as dopamine, dobutamine, orepinephrine, are not undertaken promptly. The most common cause of deathduring hospitalization after resuscitated cardiac arrests are related tothe severity of ischemic injury to the central nervous-system, e.g.,anoxic encephalopathy. The ability to resuscitate patients of cardiacarrest is related to the time from onset to institution of resuscitativeefforts, the mechanism, and the clinical status of the patient prior tothe arrest.

[0006] Focal cerebral ischemia refers to cessation or reduction of bloodflow within the cerebral vasculature resulting from a partial orcomplete occlusion in the intracranial or extracranial cerebralarteries. Such occlusion typically results in stroke, a syndromecharacterized by the acute onset of a neurological deficit that persistsfor at least 24 hours, reflecting focal involvement of the centralnervous system and is the result of a disturbance of the cerebralcirculation. Other causes of focal cerebral ischemia include vasospasmdue to subarachnoid hemorrhage or iatrogenic intervention.

[0007] Traditionally, emergent management of acute ischemic strokeconsists of mainly general supportive care, e.g. hydration, monitoringneurological status, blood pressure control, and/or anti-platelet oranti-coagulation therapy. Since 1996, tissue plasminogen activator(t-PA) or Activase®, was approved by the FDA for treatment of acutestroke. However, treatment with systemic t-PA is associated withincreased risk of intracerebral hemorrhage and other hemorrhagiccomplications. Aside from the administration of thrombolytic agents andheparin, there are no therapeutic options currently on the market forpatients suffering from occlusion focal cerebral ischemia. Vasospasm maybe partially responsive to vasodilating agents. The newly developingfield of neurovascular surgery, which involves placing minimallyinvasive devices within the carotid arteries to physically remove theoffending lesion may provide a therapeutic option for these patients inthe future, although this kind of manipulation may lead to vasospasmitself.

[0008] In both stroke and cardiac arrest, patients develop neurologicaldeficits due to reduction in cerebral blood flow. Treatments shouldinclude measures to increase blood flow to the cerebral vasculature tomaintain viability of neural tissue, thereby increasing the length oftime available for interventional treatment and minimizing neurologicdeficit while waiting for resolution of the ischemia.

[0009] New devices and methods are thus needed for augmentation ofcerebral blood flow in treating patients with either stroke or cardiacarrest caused by reduced cerebral perfusion, thereby minimizingneurologic deficits.

SUMMARY OF THE INVENTION

[0010] The invention provides vascular constriction devices and methodsfor augmenting blood flow to a patient's cerebral vasculature, includingthe carotid and vertebral arteries, while maintaining peripheralcirculation. The devices constructed according to the present inventioncomprise an aortic shunt, having first and second tubular members. Thefirst member has a first diameter suitable for passage through theaortic lumen and is expandable to a second diameter suitable forfrictionally engaging the aortic lumen. In certain embodiments, thefirst member comprises a self-expanding stent, or an expandablecylindrical or toroidal balloon. The first member has a length whichspans from the ascending aorta upstream of the brachiocephalic trunk tothe descending aorta downstream of the left subclavian artery. The firstmember also includes a lumen that communicates with proximal and distalopenings, and a side opening adapted to communicate with the carotidarteries.

[0011] The second tubular member is nested within the first tubularmember. The second member includes a lumen communicating with proximaland distal openings. The distal opening is aligned with the side openingof the first tubular member. This structure allows blood flow throughthe ascending aorta through the first member into the descending aorta,and through the second tubular member into the carotid arteries.

[0012] In another embodiment, the distal end of the second tubularmember communicates with a port or a plurality of ports mounted on anintermediate portion of the first tubular member. The port(s) areadapted to communicate with the carotid arteries. The proximal end ofthe second tubular member extends through an incision on a peripheralartery, e.g., femoral artery, outside of a patient's body and is adaptedto receive infusion of oxygenated blood or cooled solution, which passesthrough the lumen and port(s) of the second tubular member into thecarotid arteries.

[0013] In another embodiment, a cooling coil is included in the secondmember for cooling blood passing through the second member beforeflowing into the carotid arteries. A thermometer is optionally mountedin the first member, second member, and/or the cooling coil formeasuring temperature of blood flow upstream and downstream the deviceand into the carotid arteries. In certain embodiments, a pump and amechanism are included in the second member to, respectively, facilitateand to provide variable blood flow from the aorta into the carotidarteries.

[0014] The present invention also provides venous return cannulas forreceiving blood from the cerebral venous circulation. When used inconjunction with the aortic shunts described above, the venous returncannulas allow the cerebral circulation to be isolated from the systemiccirculation in selective cooling of the cerebral circulation. This isparticularly helpful in minimizing complications associated withsystemic cooling, e.g., disseminated intravascular coagulation (DIC).The cannula has an elongate tubular member having a lumen communicatingwith a proximal end and a port at a distal end. The distal port isadapted to receive venous blood from the jugular veins. An inflatablechamber is included in the distal end, and when expanded, is adapted toengage the lumens of the right and left subclavian veins at a positionwhere the jugular veins and the subclavian veins join the superior venacava. The chamber also includes first and second ports that are adaptedto receive blood from the right and left subclavian veins and pass theblood into the superior vena cava.

[0015] In using the aortic shunts described above for treating patientwith stroke and/or cardiac arrest, the aortic shunt is first advancedinto the aorta through an incision on a peripheral artery, e.g., thefemoral artery. The shunt is positioned so that the proximal opening ofthe first tubular member is upstream of the brachiocephalic trunk, thedistal opening of the first tubular member is downstream of the leftsubclavian artery, and the side opening communicates with the carotidarteries. The shunt is expanded so that the first tubular member engagesthe lumen of the aorta. Oxygenated blood flows from the ascending aortathrough the first tubular member into the descending aorta and throughthe second tubular member into the carotid arteries. Blood is cooledwhen passed through the second member. Alternatively, cooled oxygenatedblood or neuro-protective solution is infused through the proximal endof the second tubular member and passed through the ports mounted on anintermediate portion of the first tubular member. Blood flow to thebrain can be varied by varying the diameter of the second tubularmember, similar to a coarctation device, as described in Barbut, U.S.application Ser. No. 09/260,371, filed Mar. 1, 1999, incorporated hereinby reference in its entirety.

[0016] In another method using the venous return cannula, the cannula isinserted through an incision on a peripheral vein, e.g., the right orleft subclavian vein. The inflatable chamber is positioned at thejunction of the right and left subclavian veins with the superior venacava. The chamber is inflated so that the first and second ports on thechamber engages, respectively, the right and left subclavian veins.Venous blood flows from the right subclavian and left subclavian veinsthrough the first and second ports and into the superior vena cava,whereas the hypothermic blood infused through the aortic shunt into thecarotid arteries is passed from the jugular veins into the port(s) atthe distal end of the cannula. Removed venous blood is then re-cooledand pumped back into the cerebral circulation via the aortic shunt. Inthis way, isolation of cerebral and systemic circulation is maintained.

[0017] It will be understood that there are many advantages in using thepartial aortic occlusion devices and methods disclosed herein. Forexample, the devices can be used (1) to provide variable partitioning ofblood flow between cerebral and systemic circulation; (2) to augment andmaintain cerebral perfusion in patients suffering from global or focalischemia; (3) to prolong the therapeutic window in global or focalischemia; (4) to accommodate other medical devices, such as anatherectomy catheter; (5) to provide selective cooling to the cerebralvasculature; and (6) by an interventional radiologist, neuroradiologist,or cardiologist in an angiogram or fluoroscopy suite.

BRIEF DESCRIPTION OF THE DRAWINGS

[0018]FIG. 1A depicts an embodiment of the aortic shunt according to thepresent invention.

[0019]FIG. 1B depicts a cross-sectional view of the aortic shunt of FIG.1A through line B-B.

[0020]FIG. 1C depicts a cross-sectional view of the aortic shunt of FIG.1A through line C-C.

[0021]FIG. 2A depicts a lateral view of another embodiment of the aorticshunt having a shorter lumen for passage of aortic blood flow.

[0022]FIG. 2B depicts an oblique view of the aortic shunt of FIG. 2A.

[0023]FIG. 3 depicts an embodiment of a venous return cannula insertedin the superior vena cava.

[0024]FIG. 4 depicts the aortic shunt of FIG. 1A and the venous returncannula of FIG. 3 performing selective cerebral perfusion.

[0025]FIG. 5 depicts another embodiment of the aortic shunt including acooling coil.

[0026]FIG. 6 depicts another embodiment of the aortic shunt having athermostat and a thermometer mounted in its cooling coil.

[0027]FIG. 7 depicts another embodiment of the aortic shunt capable ofvarying the diameter of the cooling coil.

[0028]FIG. 8 depicts another embodiment of the aortic shunt having anextended cooling coil.

[0029]FIG. 9 depicts another embodiment of the aortic shunt havingradiopaque markers mounted on its inflation seal.

[0030]FIG. 10A depicts another embodiment of the aortic shunt integratedwithin an expandable stent.

[0031]FIG. 10B depicts the aortic shunt of FIG. 10A deployed in theaorta.

DETAILED DESCRIPTION

[0032] An embodiment of an aortic shunt constructed according to thepresent invention useful for providing selective cerebral perfusion inpatients suffering from stroke and cardiac arrest is depicted in FIG. 1.The shunt comprises first tubular member 20 and second tubular member 30nested within the first member. The first member has lumen 25 thatcommunicates with proximal opening 21 and distal opening 22 and isadapted to receive aortic blood flow. The first member also includes aside opening adapted to communicate with the carotid arteries. Anexpansion mechanism 10, such as an inflation seal, cylindrical balloon,or toroidal balloons, is mounted on first tubular member 20 andcommunicates with inflation lumen 35. The aortic shunt can be collapsedto facilitate its insertion and passage through the aorta and can beexpanded to frictionally engage the lumen of the aorta by infusing air,gas, or saline through inflation lumen 35.

[0033] Second tubular member 30 has a proximal end, a distal end, andlumen 31. The distal end communicates with at least one port mounted onan intermediate portion of first tubular member 20. The port(s) areadapted to communicate with the carotid arteries. The proximal endextends outside of the patient's body and is adapted to receiveoxygenated and/or hypothermic blood. FIGS. 1B and 1C providecross-sectional views of the aortic shunt of FIG. 1A through sectionalline B-B and C-C, respectively.

[0034]FIGS. 2A and 2B depict a lateral and an oblique view of anotherembodiment of the aortic shunt. The shunt comprises second tubularmember 30 nested within first tubular member 20. Lumen 25 of firsttubular member 20 is adapted to receive aortic blood flow. Lumen 31 ofsecond tubular member 30 is adapted to receive oxygenated and/orhypothermic blood which is passed through ports 33 to perfuse thecarotid arteries. Manometer 70 is included in second tubular member 30for measuring the pressure of the perfused blood. The first tubularmember depicted in FIGS. 2A and 2B has a length that is shorter thanthat of the first tubular member in FIG. 1A. The length of the firsttubular member generally spans from the ascending aorta upstream of theright brachiocephalic artery to the descending aorta downstream of theleft brachiocephalic artery.

[0035] An embodiment of the venous return cannula that facilitatesremoval of hypothermic venous blood from the cerebral circulation isdepicted in FIG. 3. The cannula comprises an elongate tubular memberhaving a proximal end, a distal end, and lumen 43. The lumencommunicates with 1, 2, 3, 4, 5, 6, 7, 8, or any other number of distalports 48 which are adapted to receive venous blood from right jugularvein 123 and left jugular vein 124. The distal end of the cannula hasinflatable chamber 40 that communicates with an inflation lumen (notshown) and upon expansion, is adapted to engage the lumen of nightsubclavian vein 121 and the lumen of left subclavian vein 122.Inflatable chamber 40 comprises first port 45 and second port 46, whichare adapted to receive blood from right subclavian artery 121 and leftsubclavian artery 122, and pass the received blood into superior venacava 120 through ports 44. In this way, the cannula maintains isolationof hypothermic jugular circulation from the subclavian circulation.

[0036]FIG. 4 depicts the use of the aortic shunt of FIG. 1A and thevenous return cannula of FIG. 3 in providing selective cerebralperfusion. The aortic shunt, placed in a collapsed state, is firstinserted into the aorta through a peripheral artery, e.g., the femoralartery. The shunt is positioned such that proximal opening 21 of firsttubular member 20 is upstream of the right brachiocephalic artery,distal opening 22 is downstream of the left brachiocephalic artery, anddistal port(s) 33 of second tubular member 30 communicate with thecarotid arteries. First tubular member 20 is then expanded to engage thelumen of the aorta. Oxygenated blood, optionally cooled by an externalcooler, is infused through lumen 31 and ports 33 of second tubularmember 30 to perfuse the cerebral vasculature, while oxygenated bloodentering the ascending aorta is passed through proximal opening 21,lumen 25, and exits distal opening 22 to perfuse the peripheral organs.

[0037] In use, the venous return cannula of FIG. 3 is inserted through aperipheral vein, e.g., the femoral vein, to position inflatable chamber40 at the junction of right subclavian vein 121 and left subclavian vein122 within superior vena cava 120. The chamber is inflated so that firstport 45 engages the lumen of right subclavian vein 121 and second port46 engages the lumen of left subclavian vein 122. Blood flows from theright and left subclavian veins through the first and second ports intothe superior vena cava. Hypothermic blood infused to the cerebralvasculature is returned to right jugular vein 123 and left jugular vein124 and passed into ports 48 at the distal end and lumen 43 of theelongate tubular member. The removed deoxygenated blood is passedthrough bypass-oxygenator machine 49, a cooler, a pump, and the cooledoxygenated blood is returned to the cerebral circulation through secondtubular member 30 of the aortic shunt. The circuit of blood flowprovided by the aortic shunt and the venous return cannula isolatescerebral circulation from systemic circulation, thereby providingselective cerebral perfusion and avoiding complications associated withsystemic cooling, e.g., disseminated intravascular coagulation.

[0038] It will be understood that the aortic shunt disclosed herein canbe used independently without the use of the venous return cannula. Awarming blanket is generally required to keep systemic body temperatureat approximately 37° C.

[0039] Another embodiment of the aortic shunt having a cylindricalcooling coil is depicted in FIG. 5. Cooling cylinder 50, having aproximal end, a distal end, and lumen 51, is nested within lumen 25 ofexpandable first tubular member 20. The distal end of the cooling coilhas distal port 52 that communicates with the side opening of the firsttubular member. The cooling coil is generally surrounded by aninsulating sleeve. In other embodiments, the distal end has a pluralityof distal ports. The distal end of first tubular member 20 communicateswith inflation lumen 53. Internal cooling using a cooling coil isadvantageous over external cooling using a cooler in that risk ofinfection introduced by external equipment and tubing is minimized.

[0040] In another embodiment, a thermometer and a thermostat areincluded in the cooling cylinder as depicted in FIG. 6. Thermometer 56,which measures the temperature of the hypothermic blood exiting coolingcylinder 50 and entering the carotid circulation, is mounted on thedistal end of the cylinder. In certain embodiments, the cooling cylinderalso includes a collar (not shown) capable of varying the aperture oflumen 51 of the cooling cylinder, thereby adjusting flow rates ofhypothermic blood exiting distal port 52. Adjustable thermostat 55communicates with thermometer 56 and the collar to provide variable andcontrolled hypothermic perfusion to the brain.

[0041] In use, first tubular member 20 is inserted and positioned in theaorta such that the proximal opening of the first tubular member isupstream of right brachiocephalic artery 130, the distal opening of thetubular member is downstream of left brachiocephalic artery 131, anddistal port 52 of cooling cylinder 50 communicates with the carotidarteries. First tubular member 20 is then expanded to engage the lumenof the aorta. Oxygenated blood flows from the ascending aorta throughlumen 51 of cooling cylinder 50 into the carotid arteries to perfuse thecerebral vasculature. Aortic blood entering the ascending aorta alsoflows through lumen 25 of first tubular member 20 into the descendingaorta to perfuse the peripheral organs, protected from the effects ofcerebral cooling. The cooling cylinder is capable of accommodatingapproximately up to 1 liter/min of the normal cerebral blood flow. Ascooling proceeds, the flow rate of hypothermic blood can be reduced to aminimum of approximately 200 milliliter/min (the amount required by acooler brain) by adjusting the collar, thereby reducing the aperture ofthe cooling cylinder. The smaller aperture of the cooling cylinder isgenerally desirable for insertion of the aortic shunt through aperipheral artery.

[0042] In another embodiment, the cooling cylinder is constructed tohave variable diameters to accommodate blood flow from 200 cc/min to 3liters/min through distal port 52 as depicted in FIG. 7. As the innerdiameter of the cooling cylinder increases, the proportion of aorticblood and hence cardiac output channeled into the brain increases,thereby increasing cerebral perfusion. In a dysregulated brain, thistranslates into increased cerebral blood flow, i.e., coarctation of theaorta. In this way, both cerebral cooling and increased cerebralperfusion can be accomplished simultaneously. In circumstances wherehypothermic perfusion is not desired, the cooling system can be turnedoff while increased cerebral perfusion continues.

[0043] A cooling cylinder having the length of approximately 5 to 7 cmusually is not long enough to provide sufficient cooling at 1 Liter/min.FIG. 8 depicts another embodiment of the aortic shunt having tubularmember 60 extending proximally into the ascending aorta to provideadditional length for cooling. The added tubular member can have alength of up to approximately 10 cm.

[0044] In another embodiment, the aortic shunt includes radiopaquemarkers 65 mounted on the proximal and distal ends as depicted in FIG.9. The markers ensure correct positioning of the shunt in the aorta,i.e., on either side of the cerebral takeoffs. Cooling cylinder 50 alsoincludes pump 75 for enhancing blood flow through distal port 52. Thepump is especially helpful in patients with low cardiac output, such asin cardiac arrest. Suitable pumps are described in Barbut, U.S.application Ser. No. 09/362,992, filed Jul. 27, 1999, incorporatedherein by reference in its entirety.

[0045] In another embodiment, the cooling cylinder is mounted within astent as depicted in FIGS. 10A and 10B. The stent is made of aself-expanding material, e.g., nitinol, or may be expanded by a stentdeployment catheter. In use, the aortic shunt, having stent 70 in acollapsed state, is inserted and positioned in the aorta such that theproximal opening of the stent is upstream of the right brachiocephalicartery, the distal opening of the stent is downstream of the leftbrachiocephalic artery, and distal port 52 of cooling cylinder 50communicates with the carotid arteries. Stent 70 is then expanded toengage the lumen of the aorta. Oxygenated blood flows from the ascendingaorta through lumen 51 of cooling cylinder 50 into the carotid arteries(at approximately 1 Liter/min) to perfuse the cerebral vasculature.Aortic blood entering the ascending aorta also flows through lumen 75 ofstent 70 (at approximately 4 Liters/min) into the descending aorta. Inthis manner, selective hypothermic cerebral perfusion is achieved.

[0046] The length of the aortic shunt will generally be between 3 to 20centimeters, preferably approximately between 10 and 15 centimeters. Theinner diameter of the expanded aortic shunt will generally be between 2and 4.5 centimeters, preferably approximately between 3.0 and 3.5centimeters. The length of the cooling cylinder will generally bebetween 3 to 20 centimeters, preferably approximately 10 and 15centimeters. The inner diameter of the cooling cylinder will generallybe between 0.3 and 3.0 centimeters, preferably approximately between 0.5and 1.5 centimeters. The foregoing ranges are set forth solely for thepurpose of illustrating typical device dimensions. The actual dimensionsof a device constructed according to the principles of the presentinvention may obviously vary outside of the listed ranges withoutdeparting from those basic principles.

[0047] Although the foregoing invention has, for the purposes of clarityand understanding, been described in some detail by way of illustrationand example, it will be obvious that certain changes and modificationsmay be practiced which will still fall within the scope of the appendedclaims. It will also be understood that any feature or features from anyone embodiment, or any reference cited herein, may be used with anycombination of features from any other embodiment.

What is claimed is:
 1. An aortic shunt, comprising: a first tubularmember expandable between a first diameter suitable for passage throughthe lumen of the aorta and a second diameter that frictionally engagesthe lumen of the aorta, the first tubular member having a length thatspans from the ascending aorta upstream of the brachiocephalic trunk tothe descending aorta downstream of the left subclavian artery, the firsttubular member having a proximal opening, a distal opening, and a lumentherebetween; and a second tubular member having a proximal end, adistal end, and a lumen therebetween, the distal end of the secondtubular member communicating with a port mounted on an intermediateportion of the first tubular member, the port adapted to communicatewith the carotid arteries when in use, the proximal end of the secondtubular member extending to a position outside of the patient's body andadapted to receive infusion of oxygenated blood, wherein, during use,oxygenated blood flows through the second tubular member into thecarotid arteries while blood from the ascending aorta flows through thefirst tubular member into the descending aorta.
 2. The aortic shunt ofclaim 1, wherein the lumen of the second tubular member communicateswith a plurality of ports at the distal end of the second tubularmember.
 3. The aortic shunt of claim 1, wherein the first tubular memberis a stent.
 4. The aortic shunt of claim 1, wherein the first tubularmember is a cylindrical balloon, and wherein the shunt further comprisesan inflation lumen that communicates with the first tubular member. 5.The aortic shunt of claim 1, wherein the first tubular member furthercomprises a balloon disposed about a portion of the first tubularmember, wherein the balloon inflates to isolate a portion of the firsttubular member where the port of the second tubular member communicateswith the carotid arteries from blood flow in the aorta.
 6. The aorticshunt of claim 5, wherein the first tubular member is a stent.
 7. Theaortic shunt of claim 5, wherein the first tubular member is acylindrical balloon, and wherein the shunt further comprises aninflation lumen that communicates with the first tubular member.
 8. Theaortic shunt of claim 1, further comprising a manometer mounted in thefirst tubular member.
 9. The aortic shunt of claim 1, wherein the firsttubular member further comprises radiopaque markers at the proximal endand the distal end.
 10. A method for treating stroke and cardiac arrest,comprising the steps of: providing an aortic shunt comprising a firsttubular member having a proximal opening, a distal opening, and a lumentherebetween, and a second tubular member having a proximal opening, adistal end, and a lumen therebetween, the distal end of the secondtubular member communicating with a port mounted on an intermediateportion of the first tubular member; advancing the aortic shunt into theaorta; positioning the shunt so that the proximal opening of the firsttubular member is upstream of the brachiocephalic trunk, the distalopening of the first tubular member is downstream of the left-subclavianartery, and the distal port of the second tubular member communicateswith the carotid arteries; expanding the shunt so that the first tubularmember engages the lumen of the aorta; and infusing oxygenated bloodthrough the lumen of the second tubular member into the carotidarteries.
 11. The method of claim 10, wherein the lumen of the secondtubular member communicates with a plurality of ports at the distal endof the second tubular member.
 12. The method of claim 10, wherein thefirst tubular member is a stent.
 13. The method of claim 10, wherein thefirst tubular member is a cylindrical balloon, and wherein the shuntfurther comprises an inflation lumen that communicates with the firsttubular member.
 14. The method of claim 10, wherein the first tubularmember further comprises a balloon disposed about a portion of the firsttubular member, wherein the balloon inflates to isolate a portion of thefirst tubular member where the port of the second tubular membercommunicates with the carotid arteries from blood flow in the aorta. 15.The method of claim 14, wherein the first tubular member is a stent. 16.The method of claim 14, wherein the first tubular member is acylindrical balloon, and wherein the shunt further comprises aninflation lumen that communicates with the first tubular member.
 17. Themethod of claim 10, wherein the shunt further comprises a manometermounted in the first tubular member.
 18. The method of claim 10, whereinthe first tubular member further comprises radiopaque markers at theproximal end and the distal end.
 19. The method of claim 10, wherein theoxygenated blood is cooled oxygenated blood.
 20. The method of claim 10,further comprising the step of inserting the shunt into the femoralartery.